USB standard connectors are widely used in the computer and electronic consumer products. It can be easily used to connect a peripheral device with a host computer without rebooting of the host computer and ensure fast transmission rate. Due to the special configuration of the USB connectors, a USB plug can only be inserted into a USB socket in a given orientation. A mark is usually provided on an external surface to help user to identify the correct plug-in orientation, however, majority of users still often find it is difficult to recognize the correct plug-in orientation, because the metal shell of the USB plug has identical shape formed at opposite sides.
As shown in FIGS. 1a and 1b a conventional USB socket 80 generally comprises a body 81, a plate member 82, a shell 83 and two pairs of spring contacts 84. The plate member 82 is integrally formed with the body 81, and extruded from the body 81 towards an opening end of the shell 83. The shell 83 is usually metal-made and encloses around the whole body 81 and the plate member 82. The two pairs of spring contacts 84 are fixed in the plate member 82 and arranged in parallel along a lower side of the plate member 82. An upper space 85 and a lower space 86 are respectively defined in the USB socket 80 between the plate member 82 and the shell 83.
FIGS. 2a and 2b illustrate a conventional USB plug 90, which comprises a body 91, a plate member 92, a shell 93 and two pairs of electrode contacts 94. The plate member 92 is integrally formed at a lower side of the body 91, and extruded from the body 91 towards an opening end of the shell 93. The shell 93 is usually metal-made and encloses around the whole body 91 and the plate member 92. The electrode contacts 94 are fixed in the plate member 92 and the body 91 are arranged in parallel along an upper side surface of the plate member 92 corresponding to the spring contacts 84 of the USB socket 80. A space 95 is defined in the USB plug 90 between the plate member 92 and the shell 93.
When the conventional USB plug 90 is connected to the conventional USB socket 80 as shown in FIG. 3, first the front end of the USB plug 90 is inserted into the upper and lower spaces 85 and 86 of the USB socket 80. The plate member 82 of the USB socket 80 is inserted into the space 95 of the USB plug 90. The electrode contacts 94 of the USB plug 90 are electrically connected to the corresponding spring contacts 84 of the USB socket 80.
It can be noted that there is only one single plate member 92 being nonsymmetrically extruded from the lower side of the body 91, therefore the USB plug 90 can only be correctly connected to the USB socket 80 in an upside plug-in orientation as shown in FIG. 3. If one of the USB socket 80 and the USB plug 90 is reversed, for example, when the USB socket 80 remains in the upside orientation as shown in FIGS. 1 and 3 and the USB plug 90 is reversed into an upside down orientation, or alternatively when the USB plug 90 remains in the upside orientation as shown in FIGS. 2 and 3 and the USB socket 80 is reversed into an upside down orientation, a correct connection can not be established between the USB plug 90 and the USB socket 80.
In order to identify the correct plug-in orientation of the USB connectors, usually an identify mark 96 is provided on an external surface of the USB plug 90 as can be seen from FIGS. 2 and 3. However, sometimes the connection between the USB connectors is still unavoidable from incorrect operations. If an incorrect plug-in operation is acted under a compelling force, permanent damages on the hardware of the USB connectors may occur.
In order to solve the above problems of the conventional USB connectors, a Japanese patent of application No. JP 2003-217728 had disclosed an improved USB socket which is adapted for connecting with a conventional standard USB plug in a reversible way to overcome the above defects.
As shown in FIG. 4, a first example according to the above patent provides a USB socket 200, which comprises a body 201, a plate member 202, a shell 203 and spring contacts 204. Wherein the plate member 202 is integrally formed at a middle of the body 201 and extrude from the body 201 towards an opening end of the shell 203. The shell 203 encloses around the whole body 201 and the plate member 202. More particularly, each one of upper and lower sides of the plate member 202 is provided with two pairs of spring contacts 204. An upper space 205 and a lower space 206 are symmetrically defined in identical shape in the USB socket 200 at opposite sides of the plate member 202. Due to the symmetrical configuration of the USB socket 200, when a user intends to connect the conventional USB plug 90 to the USB socket 200 as shown in FIG. 4, he/she can just adjust the vertical position of the USB plug 90 in order to make the space 95 of the USB plug 90 to be in line with the plate member 202 of the USB socket 200 no matter whether the plug-in orientation of the USB plug 90 is in an upside or an upside down orientation, that is to say, the conventional USB plug 90 can be reversibly connected to the USB socket 80 in both upside and upside down plug-in orientations.
However the defects of the above described USB socket 200 is that the opening size of the shell 203 of the USB socket 200 is unmatched to the conventional standard USB plug 90, and the vertical position of the USB plug 90 have to be adjusted in order to make the space 95 of the USB plug 90 in line with the plate member 202 of the USB socket 200. Additionally, the metal-made shell 93 of the USB plug 90 may cause the spring contacts 204 of the USB socket 200 to be short cut during the plug-in connection, therefore the reliability of this type of USB socket 200 is low.
As shown in FIGS. 5, 6 and 7, another example according to the above patent provides a USB socket 300 comprising an upper slide 302 and a lower slider 302′ slidably received in a shell 303. A pair of upper spring contacts 304 and a pair of lower spring contacts 304′ are respectively provided on a lower side of the upper slider 302 and an upper side of the lower sliders 302′. In particular, two springs 305 and 305′ are respectively connected at rear ends of the upper and lower sliders 302 and 302′ to provide compressive resilient energy to the sliders 302 and 302′.
When the USB plug 90 is connected to the USB socket 300 in an upside plug-in orientation as shown in FIG. 6, the upper slider 302 will be inserted into the space 95 of the USB plug 90, and the lower slider 302′ will be retracted inwardly by the intrusion of the plate member 92 of the USB plug 90. When the USB plug 90 is connected to the USB socket 300 in a reversed upside down plug-in orientation as shown in FIG. 7, the lower slider 302′ will be inserted into the space 95 of the USB plug 90, and the upper slider 302 will be retracted inwardly by the intrusion of the plate member 92 of the USB plug 90. If the USB plug 90 is plugged out from the USB socket 300, the retracted slider 302 or 302′ will return to the original position by the resilience of the spring 305 or 305′.
However, the structure of the USB socket 300 of the above patent is very complicated, so the manufacturing cost must be expensive, and moreover it does not illustrate a reliable electrical connection between the spring contacts 304 and 304′ and terminal pins of the USB socket 300.
Therefore, there exists an object for the present invention to provide an improved type of USB connector in order to solve the problems and defects of the prior art.